This invention relates to reducing vibration in froth flotation cells wherein the source of the vibration is the rotor or mixer assembly.
Froth flotation cells are used to separate mineral values from mineral wastes. An ore is finely ground and suspended as a water-based slurry or pulp in a flotation cell. An impeller or rotor is turned at a high speed in the slurry to suspend the mineral particulates and distribute or disperse air bubbles into into the slurry. The mineral values attach to the air bubbles. The bubbles with the entrained mineral values then rise to form a froth atop the pulp or slurry pool. The froth overflows a weir and is collected in a launder for further processing. Examples of flotation cells are described in U.S. Pat. No. 5,611,917 to Degner, U.S. Pat. No. 4,737,272 to Szatkowski et al., U.S. Pat. No. 3,993,563 to Degner, U.S. Pat. No. 5,219,467 to Nyman et al., U.S. Pat. No. 5,251,764 to Niitti et al., and U.S. Pat. No. 5,039,400 to Kallioinen et al. In the flotation machines of some of these references, air is supplied to the pulp or slurry via a separate pumping mechanism.
During flotation cell operation, the rotation of the impeller can generate vibration in the flotation cell mechanism or drive assembly. Sometimes, these vibrations can become pronounced, thus dissipating the vibrational energy throughout the flotation cell superstructure or a portion thereof.
Significant vibration can also be generated in other types of industrial mixers such as draft tube mixers. Draft tube mixers generally comprise a propeller or rotor which pumps large volumes of sludges or slurries. In the anaerobic digestion of sewage sludges, these mixers act as low head, high volume sludge pumps. The mixing propellers are mounted for rotation about a vertical axis for mixing the nonhomogeneous components of the sewage sludge, thereby preventing stratification, enhancing thermal homogeneity, and for effecting surface agitation which breaks up surface scum.